Recording Details

Abstract

Some recent searches for quantum gravity signatures using
observations of distant astrophysical sources will be discussed, focusing on
the search for Lorentz invariance violation (LIV) in the form of a dependence
of the photon propagation speed on its energy. Fermi gamma-ray space telescope
observations of ~8 keV to ~30 GeV photons from a short (
burst (GRB 090510) at a cosmological distance (z = 0.903), enabled for the
first time to put a direct time of flight limit on a possible linear variation of
the speed of light with photon energy that is beyond the Planck scale.
Parameterizing

|v/c-1| = E/E_{QG} our most conservative limits are
E_{QG}/E_{Planck}

> 1.2, while less conservative limits are up to 1-2
orders of

magnitude stricter. Other types of astrophysical searches
for LIV will be briefly outlined, along with some prospects for the future.